1. Field of the Invention
The present invention relates to a lighting device used to light the inside of the mouth during dental diagnosis and treatment.
2. Prior Art
Generally, a lighting unit for dental diagnosis and treatment has a lighting device at the end of a swivel arm so that the lighting direction from an upper oblique position to the dental chair and the lighting device holding position can be adjusted as desired.
This lighting device is generally called an astral lamp. The reflection plate of the lighting device is curved so that the light is effectively cast to the inside of the mouth during dental diagnosis and treatment. The light source lamp of the lighting device is disposed inside the curved reflection plate surface so that no shadow is generated inside the mouth even when the dentist intercepts a part of the light beam of the lighting device. The front side (patient side) of the light source lamp is covered with a light source cover. Except the light source cover, the front surface of the conventional lighting device is optically open to obtain better lighting efficiency.
Therefore, when the patient wishes to look at a treatment section, for example, a false tooth section, the patient or the dentist (or the dentist's assistant) must hold a hand mirror to look at the inside and vicinity of the patient's mouth. This is inconvenient and troublesome, and takes a long time to adjust the hand mirror surface at the optimum angle, imposing a great burden on the patient and the dentist.
In addition, light must be cast into the mouth of the patient using a lighting device when looking at the inside of the mouth using a mirror. In this case, light must be cast away from the hand mirror. Therefore, the position and the lighting direction of the lighting device must be finely adjusted. Furthermore, when the dentist instructs the patient how to mount false teeth, both hands of the dentist and those of the patient should be left free for higher working efficiency. However, since the patient or the dentist must hold the hand mirror, working efficiency is reduced.